Archaeologists work inside the Blombos Cave in South Africa in 2008 when they discovered the100,000 year old toolkits. Christopher Henshilwood on right, Grethe Pedersen in foreground. Image: Science/AAAS

The nacre and inside of the abalone shell after removal of the grindstone. The red deposit is the ochre rich mixture that was in the shell and preserved under a cobble grinder. Image courtesy of Grethe Moell Pedersen

The toolkit with abalone shell before excavation from the 100,000 year-old Middle Stone Age levels at Blombos Cave in South Africa. Image: Science/AAAS

Abalone shell-you can see some of the ochre rich deposit. Image: Science/AAAS

Karen van Niekerk and Grethe Moell Pedersen point to the 100,000-year-old abalone shell with ochre before recovery in 2008. Image courtesy of Christopher Henshilwood